Recently, research has been completed related to techniques which seek to provide “fairness” (i.e., a minimal allocated bandwidth) and quality of service (“QoS”) guarantees for wireless local area networks (WLANs). For example, co-pending U.S. patent application Ser. No. 10/788,460 entitled “Methods and Devices for Providing a Relative Level of Fairness and QoS Guarantees to Wireless Local Area Networks” discloses techniques which divide a contention free period (“CFP”) into a plurality of slots. Thereafter, only non-interfering access points are allowed to transmit during one or more slots which have been allocated or assigned to each access point (“AP”). By only allowing non-interfering access points to transmit during an assigned or allocated slot, problems (e.g., hidden node and overlapping cell problems) associated with providing fairness and QoS guarantees are eliminated.
Co-pending U.S. patent application Ser. No. 10/788,460 sets forth one criteria which may be used to determine the number of CFP slots to assign to an AP, that being, assigning slots to APs such that a lower bound of AP slot-to-user ratios is maximized. Based on this criteria, co-pending U.S. patent application Ser. No. 10/788,460 ensures that every AP has at least one slot during which it is allowed to transmit. That said, co-pending U.S. patent application Ser. No. 10/788,460 is not necessarily directed at determining how long an access point will be allowed to transmit during a CFP (i.e., how many transmission slots should be assigned to each access point) or when an access point will be allowed to transmit (i.e., during which slots, hereafter referred to sometimes as “slot sequence”).
It is therefore desirable to provide methods and devices for determining the number of transmission slots to assign to each AP and the slot sequence for each AP based on a maximal, lower bound of AP slot-to-user ratios. Collectively, the assignment of slots, slot sequence (as well as other functions) may be referred to as coordinating AP transmissions in a WLAN during a CFP.